This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We are currently investigating properties of numerous protein domains involved in DNA and RNA ligation. Among these domains are the phosphoesterase domains of bacterial and archaeal LigD proteins, the ligase components of bacterial and archaeal RNA repair systems PnkP/Hen1, and the bacterial 3'-PO4 ligation pathway exemplified by the RtcB enzyme. In addition, we have diffracting crystals of E. coli PrrC tRNA nuclease, a novel ribotoxin (details below). Consult the following publications for representative work (all of which was carried out at the NSLS):PMID: 21208981PMID: 20616014PMID: 20399182